Friday, March 27, 2015

How Many Earthquakes in a Week- and the Meaning of Life

The question was typical. The follow-up question was definitely NOT.

Q: Hey I'm wondering how many earthquakes occur every week ? And how powerful they are......
--Rossy K

A:  The answer to your question depends on how BIG the earthquakes are that you are talking about. The smaller the earthquake, the more common they are. This means that there are probably many undetected (very small) earthquakes happening around the world every second. This also means that the really big ones - the ones that get in the news - are not very common at all.

    The US Geological Survey estimates that several million detectable earthquakes occur in the world each year. Many go undetected because they originate in remote areas or they have very small magnitudes. The National Earthquake Information Center now locates about 50 earthquakes each day, or about 20,000 a year, worldwide. They have to be above a certain minimum threshold before an effort is made to even try to locate them.

    There are far fewer large events than small earthquakes, and this table will show you how these are parsed out according to magnitude:

Frequency of Occurrence of Earthquakes
Magnitude                         Average Annually
8 and higher                       1                                             
7 - 7.9                                    15                                          
6 - 6.9                                    134                                        
5 - 5.9                                    1319                                      
4 - 4.9                                    13,000   (estimated)       
3 - 3.9                                    130,000 (estimated)       
2 - 2.9                                    1,300,000 (estimated)

    I would recommend that you visit this web-page:
    http://earthquake.usgs.gov/earthquakes/eqarchives/year/eqstats.php
    There are lots of interesting statistics here.

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Q: What’s the meaning of life?
--Rossy K

A: Ask your parents, and they will give you a start on answering that question. I just answer questions about geology.

On average you have upwards of 70 more years to figure this out yourself. That's pretty much the whole point of your being on this planet. 

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